1. Field of the Invention.
This invention relates to an improved mobile emergency medical vehicle or ambulance for over-the-road service in handling medical emergencies with greater reliability and lesser maintenance to ensure proper performance in all situations, the vehicle having a medical equipment, supply and patient module with self-supporting integral electrical generating capability to supply all electrical requirements of the module with electrical back-up being provided by the main transport engine of the vehicle.
2. Description of the Prior Art.
Previously in the manufacture of virtually all ambulances of the Type I style for over-the-road emergency medical service, a truck chassis as manufactured by a truck manufacturer has been utilized having the maximum electrical generating capacity driven by the main transport engine of the truck to supply the electrical and medical equipment requirements of the patient compartment along with the operator's compartment of the vehicle. In such cases all of the electrical requirements of the patient module, including exterior and interior lighting as well as air conditioning and heating needs of the module, have all been driven from or provided by the main truck engine requiring substantial interconnection between the main engine and the patient module. As the electrical requirements of the module have continually increased over the years and truck manufacturers have indicated the problems to be anticipated with overloading various components of the main truck engine, presently existing ambulances have required very substantial maintenance and servicing to ensure that the main truck engine is capable of meeting all of the various requirements of the patient module at all times whether the ambulance be in service or on standby duty. The typical truck chassis utilized for ambulance manufacturing has involved a maximum size electrical alternator and dual batteries, one of which provides starting power for the transport engine and the other of which provides auxiliary power for the module electrical needs. Air conditioning and heating requirements of the module have been taken from the main truck engine which has not always been satisfactory in view of the extensive modifications required to the engine components to bring both air conditioning and heating capability into the module from the transport engine.
In existing mobile emergency medical vehicles of Type I as defined by federal specifications, it is not uncommon for the main truck engine to be operated in an advanced idling condition at the scene of a medical mission in order to supply all of the electrical requirements of the vehicle and patient module. Thus, the total number of miles traveled on medical missions by such vehicle is not a true indication of the condition of the vehicle for continuing and repeated medical missions. In many such vehicles it is necessary to monitor the total running time of the engine, especially under high idling conditions to determine whether the vehicle is fully capable of performing such missions on a regular repeated basis. In warm climates the air conditioning unit driven by the main truck engine is in some cases incapable of providing adequate air conditioning to the patient module and all of the electrical requirements of such module are dependent upon the electrical generating system of the main truck engine.
Proper maintenance of emergency medical vehicles such as ambulances has been an increasing concern of the industry, especially in situations where a given vehicle may be required to perform 300-350 medical missions per month under widely varying conditions and for widely varying time periods. As the electrical requirements for the patient compartment have increased, the industry has been unable to significantly increase the onboard capability for providing all of the electrical needs of the module, being limited by the performance capability of the transport engine and its electrical generating and storage capacity. The onboard electrically-powered medical equipment has basically been limited heretofore to the 12 volt DC system supplied by the truck electrical system which has been adequate in some cases for powering electrical equipment such as improved vacuum generating pumps and the like during transport. There is an increasing need to supply both 115 volt AC as well as 12 volt DC power within the patient module to provide a much greater capability in powering newer and improved types of medical equipment. With many types of currently manufactured ambulances equipped with heavy-duty 165 ampere alternators, for example, the main truck engine must be operated at relatively high speeds, especially while standing, to meet the air conditioning and medical equipment needs of the module as well as other electrical needs such as both interior and exterior electrical lighting, sirens, flood lights, and the like.
It is highly desirable that the medical module mounted on the truck chassis be as largely self-supporting as possible to facilitate remounting of the module on a separate truck chassis with minimum modifications being required. With the module being substantially self-supporting in all its electrical requirements, the module may be more readily monitored independently of the vehicle to simplify record keeping, maintenance and servicing to ensure essentially fail-safe performance of all components of the module under widely varying conditions and service requirements.
In the situation where many modern-day ambulances having patient modules entirely dependent upon the main truck engine for its electrical requirements, as stated, the main engine must be continuously operated at the site of the medical mission to supply the electrical requirements and the main transport engine is rarely turned off to ensure that the electrical storage capacity is not unduly drained and the vehicle may subsequently refuse to start when desired. If turned off, there is real concern that the main engine may not restart due to heavy electrical loading when standing.
Within the ambulance industry it is well understood that the truck manufacturers' recommended service programs for the vehicle per se are inadequate in determining the high performance requirements of ambulance and paramedic systems. Further, in the larger cities there has been an attempt to standardize the ambulance fleets which are both privately and publicly owned to simplify maintenance and replacement part servicing of the ambulance units which are ready for use and on standby to cover existing needs as well as greater peak loads that might be anticipated at any given time. Such maintenance and servicing can be extremely costly and time consuming to ensure that all units are available for all assigned medical missions.
The desirability of separating the main engine which transports the vehicle from the electrical needs of the medical module has been a continuing problem for the industry until the problems associated therewith have been solved by the present invention.